#!/bin/bash
# echo "hello $1"

function cal
{
    case $2 in
        +)
            echo "running + here..."
            echo "`expr $1 + $3`" ;;
        -)
            echo "running  - here..."
            echo "`expr $1 - $3`" ;;   
        /)
            echo "running  / here..."  
            echo "`expr $1 / $3`";;
        *)
            echo "running  * here..." 
            echo "`expr $1 \* $3`" ;;
    esac
}

cal $1 $2 $3